BIALOWIEZA NATIONAL PARK, Poland — The two great, glowering creatures paused from their noisy feeding, silhouetted against the pencil-thin pines on the far side of a meadow, and emitted a couple of steam-train snorts.

“I think we have gone close enough,” said Michal Krzysiak, who is part of a 23-member team overseeing this sprawling park’s European bison herd and is its only veterinarian. “We may scare them away, or they may charge.”

The two bison — among the 1,500 or so here in Bialowieza, the largest concentration of the European variety in the world — took turns lowering their heads to the thick grass and ripping at it with their rough, gray tongues.

Dr. Krzysiak, 34, watched them with avid interest, the rooftops of the small village of Teremiski rising a few hundred yards behind him. At first, he said, residents of villages in and around the park were leery of the bison and worried about the impact on their properties. Yet the animals became part of the landscape and now, he said, the villagers refer to them as “our bison.”

Last month, Piotr Otawski, Poland’s deputy minister of the environment and chief nature conservator, announced a plan to codify and streamline government efforts to protect and grow the country’s herds of bison, an effort that might seem as uncontroversial as a government action can get.

Yet many farmers see the bison as a hazard to their fields and crops. The officials in charge of the country’s national forests do not always welcome the idea of more such creatures in the wild. Some business interests worry that too many new environmental rules will hobble the country’s economic expansion.

Even those who support protecting the bison cannot agree. One group of scientists thinks there are too many of them in some places and chafes under government regulations that prevent culling. Another group says the problem is not too many bison but too much human interference in their care.

“People are the biggest problem,” Dr. Krzysiak said. “By far.”

Bialowieza (pronounced bee-ah-wo-vee-EDGE-ah), resting against the Belarus border 140 miles east of Warsaw, is one of the last remaining stretches — and, at 580 square miles, the largest — of the primeval forests that once carpeted all of northern Europe. Its vast expanses of pine and birch, of sucking marsh and sun-painted clearings, are home to moose, wolves, lynxes, beavers, wild boars and enough birds to keep Audubon busy until winter.

The park makes much of its royal and czarist past, its historic buildings lovingly restored in the traditional, ornate Polish manner and adorned with images of the Romanovs.

But the stars of the park are the European bison, one of the great environmental success stories of postwar Europe, which have become symbols of the Polish nation.

“They are a very charismatic species,” said Rafal Kowalczyk, the director of the Mammal Research Institute on the park’s edge. “I would say they have become iconic. Many Polish companies use them in their logos.”

Protected in royal hunting enclosures, of which Bialowieza is a surviving example, first by the kings of Poland and then by the czars, the animals were hunted for food during war after war, retreating deeper into the forest, until the last wild one fell to a hunter’s bullet in 1919 here in Bialowieza. The European bison (Bison bonasus), cousins of the American variety, survived only as a handful of individuals, mostly in zoos in Berlin and elsewhere across Central Europe.

But beginning in 1951, Poland’s Communist government — as part of its campaign to reinvigorate the country after the war — began an audacious campaign to revive the species and reintroduce it into what was believed to be its favored habitat, the thick forests of the Polish borderlands.

Within a few decades, the herds had grown to more than 1,000 specimens, an astonishing resurrection. Today, more than 5,000 bison live in captivity or wild herds here in Bialowieza, scattered across a few other areas in Poland and gathered in relatively smaller numbers in France, Germany, the Netherlands, Romania, Ukraine and a few other countries.

“It is a very sexy story,” Mr. Otawski said.

But it is not enough.

“We want to have 10,000 in Europe,” Dr. Krzysiak said. “That is the minimum count where we think the population can be considered safe and protected.”

The plan Mr. Otawski has proposed involves changing several of the rules regarding the handling of the bison and adding regulations that would, for instance, require health checks before an animal can be moved from one area to another.

He also wants the Polish government to commit to a certain level of money every year to maintain the herds, rather than depending on European Union and other outside aid, as the country does now. With luck, he said, the rules will move through the Polish bureaucracy and be enacted by year’s end.

Not everyone, he acknowledges, is on board.

“Some of these NGOs, they are not happy to have the minister being so active in the field,” Mr. Otawski said. “They want to operate without government interference.”

Wanda Olech-Piasecka, a professor in the department of animal genetics at the Warsaw University of Life Sciences and chairwoman of the European Bison Friends Society, said he got that right.

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Some 1,500 European bison, cousins of the American variety, are in Bialowieza National Park, the largest concentration of the creatures in the world.CreditMaciek Nabrdalik for The New York Times

“Look, he is a guy who is producing law,” she said. “Sometimes, it is very difficult to make life conform with law.”

If anything, the bureaucracy must be cut back, she said, allowing those in the field, like her group, to do what is necessary, including the culling of herds in some places.

Already, she said, the herd in Bialowieza has grown too large for the park. Each winter, it moves farther outside the park’s boundaries and into neighboring farms. And try getting permission from Warsaw to kill a few extra bison, she said: “You must wait and wait, for months. These rules were created by clerks who were never in the field.”

Mr. Kowalczyk, at the mammal institute, said the struggle over who has control over the bison missed the real problem: that those who have been in charge of protecting the animals, in the government and in the field, have refused to heed scientific evidence that they have been mismanaging the herds.

“Who says this is a forest species?” he said. “People say, ‘Oh, it is a creature of the forest.’ So when they reintroduce the bison, they do it into the forest.”

But they are not forest animals, he said. Given the choice, they would greatly prefer open plains and river valleys, he said, just like their American cousins. The only reason they live in Poland’s forests is they were placed there so the kings could hunt them, he said.

Of the almost 1,500 bison in the park, about 1,000 roam wild and about 500 are in captivity, kept in sprawling but zoolike enclosures where tourists and school groups can look at them. The wild herd at Bialowieza is one of seven such wild herds across Poland. It is by far the largest; some are as small as a few dozen creatures.

An important goal, Dr. Krzysiak said, is convincing those whose farms surround the park and other national forests that the bison pose little, if any, threat. One way the government does this is by paying promptly and lavishly for any damage the animals do on private property, and another is by enlisting the farmers in profitable projects like growing hay to feed the bison over the winter.

“It is understandable why people are afraid of the damage that these animals can do,” said Andrzek Sitowski, 74, a retired farmer who moved to Lublin to be near his grandchildren. “They are big, and they are not calm, like cows.”

Mr. Sitowski found himself one recent afternoon wandering a field on the outskirts of Budy, a small village not far from his former farm. He stared toward a lone bull bison hugging the distant tree line.

“Still,” he said, “they are magnificent animals.”

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A version of this article appears in print on , on Page A5 of the New York edition with the headline: Poland Works to Ensure Bison Multiply, but Some Prefer Subtraction . Order Reprints | Today’s Paper | Subscribe